Toyota coolant

[KEnhoffer]

I just changed the coolant in my wife's Toyota Sienna with Toyota red coolant purchased from the dealer at over twice the price of Zerex and other common brands. I prefer to use a red coolant, although I understand mixing with green is OK. Does any TDR member know what aftermarket coolant is red like the Toyota anti-freeze?

 

[BK]

I'm gonna try and find a pdf file that spoke about this, or the link to it. Colors dont mean a darn thing between manufacturere's OEM fluids and aftermarket. BEWARE.







found a reprint in part of the article I had seen...



In the middle it addresses imports and what makes up their coolants...





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"Keeping It Cool

by Paul Weissler



August 1999. Coolant incompatibility and the usual assortment of great service tips highlight the coverage from this year's NARSA convention.



The coolant inside each of the reservoirs-from a Toyota, a '98 Dodge Intrepid and a VW Passat-looks about the same color. It's red... well, maybe pink... or is it orange? Yup, must be that new orange OAT (organic acid technology) coolant, with the special inhibitor package that provides a promise of longer coolant life.

In reality, only one of the three is a "pure" OAT antifreeze-in the VW. And as such, Volkswagen carries no replacement recommendation. Then again, VW never has had a replacement interval, even with its conventional coolants, something no one at VW has ever explained to our satisfaction. The antifreeze in the Dodge Intrepid may be orange and contain some OAT, but it's really what we call a "hybrid," and it may be going away after a brief trial. The Toyota? It uses a traditional Japanese coolant-a high-phosphate, nonsilicate formulation.



If you want to take this whole thing a step further, look at a Dodge truck. You'll see green coolant in its reservoir. Looks about the same color as the green stuff in a Mazda, but the coolant in each is totally different. Well, at least all coolants are compatible. Or are they? As we're finding out, there's a fair amount of incompatibility among coolants, both with the new extended-life antifreezes and when mixing the new OAT coolants with what we now call "conventional" formulas.



Questions & Answers



The National Automotive Radiator Service Association (NARSA) has been wrestling with this issue, trying to sort out the confusion and see where the real-world problems exist. It has been getting coolants analyzed and talking to scientists and chemists, plus engineers at the vehicle manufacturers.



NARSA admits that it doesn't have all the answers, but it may be able to help you avoid the major pitfalls. Here are NARSA answers to some frequently asked questions. First, though, a few caveats: Many changes are occurring in coolant chemistry, and NARSA believes Daimler/Chrysler U. S. will be going to a new coolant formulation very shortly. Ford, meanwhile, has said it's considering a hybrid for its U. S. cars, but for the present is continuing with conventional American coolant.



Those caveats aside, here's a service-oriented summary of what you need to know to help minimize the chances of doing something wrong with your customers' cooling systems.



First of all, forget coolant color; it's just a dye and means nothing. GM and Texaco, which codeveloped the Dex-Cool brand of OAT antifreeze for late-model GM vehicles, picked orange to distinguish this type of antifreeze from conventional American coolant, which is green or gold. Volkswagen, which also uses an OAT formulation as mentioned earlier, has a similar dye that most of us think is pink. Toyota's traditional red dye is a totally different product. Although the orange coolant in Chrysler L/H models contains OAT, it's a custom hybrid, with Chrysler specifically forbidding the use of Dex-Cool in these cars. It would have been better if Chrysler had used some other dye color.



What kinds of coolants are out there? Aside from the limited sale of propylene glycol to environmentalists, it's ethylene glycol... about 93% ethylene glycol, that is, plus water and specific rust and corrosion inhibitors. Here's a rundown:



Conventional American coolant (green or gold) contains silicates (a long-used aluminum corrosion inhibitor) and other inhibitors. Silicates work quickly to protect aluminum, but also are depleted relatively quickly in service. They're also somewhat abrasive (being based on silicon-sand), so they've been implicated in water pump seal wear. Advocates say tests show silicates last longer than was commonly believed. And with the latest seal materials, they actually do a better job of protecting the water pump, because they both resist cavitation erosion-corrosion and "repair" any that occurs.



OAT coolant (orange or pink) contains no silicates and no phosphates. It's a blend of two or more organic acids, a specific class of inhibitors with slow-acting, long-life properties. Texaco's Havoline Dex-Cool (also sold under the Goodwrench label by GM) was the first example. Prestone and Peak also have introduced OAT coolants that are chemically compatible with Dex-Cool.



Conventional Japanese coolant (green or red) contains no silicates, but has a heavy dose of phosphates and other inhibitors, including a modest amount of one or two organic acids.



Conventional European coolant (blue or yellow) contains a low dose of silicates and no phosphates, but does include other inhibitors, including one organic acid.



Hybrid European coolant (blue or green) is similar to conventional European, but with a much greater dose of organic acids. It's a balanced formula designed to have the silicates provide the primary protection for the aluminum, then allow the organic acids to provide long-term protection.



Hybrid American coolant (green or orange) contains a moderate dose of silicates, plus a blend of organic acids.



So with all these coolants around, who uses what?



GM cars and light trucks built since the 1996 model year use Dex-Cool OAT. VW/Audis since 1998 use an OAT, but it's a different formula. The '99 Mercury Cougar uses an OAT-type coolant that's reportedly similar to Dex-Cool.





Except for the '99 Cougar, Ford U. S. vehicles use conventional American antifreeze. And except for the hybrid coolant in '98-on L/H cars (Intrepid, Concorde, 300M), so do Daimler/Chrysler U. S. vehicles.





Mercedes uses a conventional European antifreeze that has been upgraded, and may outlast the conventional stuff.





GM Opel products sold here (namely the Cadillac Catera) use Dex-Cool.





Volvos and BMWs use a hybrid European.





Japanese cars use a conventional Japanese coolant.





Korean cars use either a conventional Japanese or conventional European antifreeze. (It depends on who did the in-depth engineering for the Korean company. )





Medium-duty and heavy-duty diesel vehicles should use specific formulas, with additives that meet recommended practices of the American Trucking Association's Maintenance Council. Some OEMs use specific OAT formulations. Cummins, on the other hand, forbids pure OATs, and recommends a specific silicate-containing hybrid with heavy-duty additives as part of a "lifetime" fill maintenance program.



Some problems exist when you mix OAT coolants with the conventional stuff, or when you do an OAT retrofit. Much evidence points to the fact that if you mix conventional American antifreeze (silicated) with an OAT type in a system with virgin aluminum (that's not protected by either type), severe corrosion will result. The producers of OAT coolants approve their use in any system, provided it's been thoroughly flushed out first.

NARSA's position is more conservative (factoring in the issues raised by the vehicle makers), and is based on the assumption that all you can obtain for service is conventional American green/gold or an American orange OAT. NARSA still recommends conventional American green/gold antifreeze. Specifically, NARSA recommends the following:



Use Dex-Cool or an aftermarket OAT only in GM cars that were factory-filled with Dex-Cool. Although you can top up with any of the three OATs available, the best practice is to flush out the system first, to remove at least 90% of the old coolant.





Do not use an OAT antifreeze in any Ford product aside from the '99 Cougar. It may attack certain gasket materials (particularly in Ford modular V8s). It also can be responsible for water pump cavitation erosion-corrosion, reports Ford.





Do not use an OAT coolant in any Chrysler product. OAT has been shown to increase damage from water pump cavitation erosion-corrosion, particularly in some truck V8s. If you can't get the specific Chrysler orange hybrid, flush out the system and install a conventional American antifreeze.





In European cars equipped with a hybrid or conventional European antifreeze, use a conventional American silicated antifreeze.





In Japanese cars equipped with silicate-free coolant, rely on this bit of history: These coolants never were sold in any quantity in the U. S. Japanese cars seem to survive nicely on conventional American products, so the safe approach is to stick with them. Both Japanese silicate-free and conventional American coolants contain phosphates, so they share that key inhibitor.





On heavy-duty vehicles, stick with the OE recommendations.





For temporary use, as in a roadside emergency, mixing different coolants is better than using just plain water. But the system should be flushed out and refilled with the correct coolant as soon as possible. "

 

[KEnhoffer]

BK,



Thanks for taking the time to reply to my post. I have now been educated in the mysteries of coolants. Bottom line: I guess it is OK to use the green coolant in the Toyota and mix with the residual red coolant left in the system.



Ken

 

[BK]

'welcome.

I'm glad I was able to find a reprint of the article... it was very good. I thought I had saved it, but noooooo...

found it online again after some searching. This time I saved it to a file for future reference...